强脉冲光促进大鼠皮肤转化生长因子-β1表达的实验研究

The Stimulating Effect of Intense Pulsed Light on the Expression of Transforming Growth Factor-β1 in Rats

目的观察强脉冲光照射对SD大鼠皮肤转化生长因子-β1(Transforming growth factor-β1,TGF-β1)表达的影响,以进一步阐明强脉冲光治疗皮肤光老化可能的机制。方法随机选取15只SD大鼠,两侧背部皮肤去毛,以一侧为强脉冲光照射实验组,对侧背部皮肤作对照组。采用波长560～1200 nm、能量27 J/cm^2、脉宽3.0 ms、双脉冲方式、脉冲延时10 ms的强脉冲光照射实验组皮肤,取术前及术后4周大鼠实验侧和对照侧皮肤标本,行大鼠皮肤TGF-β1蛋白免疫组化染色定位,观察大鼠皮肤TGF-β1的分布情况以及强脉冲光照射后TGF-β1的表达变化。结果TGF-β1分布于大鼠正常皮肤全层,主要分布在细胞外结缔组织基质胶原纤维中。强脉冲光照射刺激大鼠皮肤分泌TGF-β1,实验组强脉冲光照射4周后,大鼠皮肤TGF-β1表达较对照组显著增强(P<0.001),阳性产物主要分布在细胞外结缔组织中。真皮浅层较对照组有非常强烈的棕黄色着染,同时皮肤表皮细胞亦出现明显的阳性表达产物。阳性表达区成纤维细胞数量明显增多。结论强脉冲光照射后上调大鼠皮肤TGF-β1的表达,是强脉冲光治疗皮肤光老化的内在机制。

Objective To investigate the expression of TGF-β1 after intense pulsed light （IPL） management to rat skins and elucidate the possible treatment mechanism of IPL. Methods Fifteen Sprague Dawley （SD） rats were included in the study, and the dorsal skins of subjects were irradiated by intense pulsed light with cut-off wavelength filter of 560 nm, fluence of 27 J/cm2, pulse duration of 3 ms and a double pulse duration of 10 ms. Skin biopsy from each subject from both treated and untreated （control） sites were performed on postoperative 4 weeks. The specimens were processed by immunohistochemistry （IHC） and analyzed quantitatively with microscopic photographs using imaging analysis software system. In addition, immunohistochemical staining was also employed to study the distribution of TGF-β1 in normal rat skin and the specific TGF-β1 changes after intense pulsed light irradiation. Results With skin immuno-staining detecting weakly positive expression to TGF-β1, TGF-β1 was diffusely present in the whole layers of normal rat skin, including the epidermis and ECM in dermis. Furthermore, TGF-β1 was significantly increased with intense pulsed light irradiation after 4 weeks. The more intensive brown-staining in the epithelium around the adnexal follicle and ECM in the dermis were found, which were significantly different from those of control skin sites （P〈0.001）. A number of fibroblasts were easily found in TGF-β1 rich areas. Conclusion Intense pulsed light irradiation can markedly regulate the secretion of TGF-β1 in rat skin which may be the presumable mechanisms of intense pulsed light treatment to photoaged skin.